Actuating units for a workpiece gripping and transporting jaw assembly are known having a hanger rod providing a mount boss depending therefrom and supporting a pneumatic cylinder below and parallel to said rod having a piston and a piston rod projecting from the cylinder. Heretofore jaw mount assemblies have been mounted upon the piston rod for feed movements therewith. Jaw assemblies have been mounted upon such jaw mount assemblies carrying a pair of opposed pivotal jaws adapted for gripping and transporting a workpiece in accordance with reciprocal movements of the piston rod relative to its supporting cylinder, as in U.S. Pat. Nos. 3,013,835 and 3,127,026.